UNIVERSITY    OF    CALIFORNIA    PUBLICATIONS. 


University  of  California— College  of  Agriculture, 

AGRICULTURAL  EXPERIMENT  STATION. 

E.  W.  HILGARD,  Director. 


ORANGE  AND  LEMON  ROT. 


By  C.  W.  WOODWORTH. 


NAVEL  ORANGE,  ONE  FOURTH  SHOWING  THE  EFFECT  OF  THE  ROT. 


BULLETIN  No.  139. 


(Berkeley,  February,  1902.) 


SACRAMENTO: 
a.  j.  Johnston,    :    :    :    :    :    superintendent  state  printing. 

1902. 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  California,  Davis  Libraries 


http://www.archive.org/details/orangelemonrot139wood 


ORANGE  AND  LEMON  ROT. 


By  C.  W.  WOODWORTH. 


The  present  season  has  been  more  than  usually  favorable  to  the  decay 
of  oranges,  especially  in  early  shipments.  Every  year  the  loss  from  the 
rotting  of  both  oranges  and  lemons  is  very  considerable.  The  cause  of 
the  rot  and  the  precautions  that  should  be  taken  to  avoid  the  trouble 
are  very  rarely  understood  by  those  who  handle  the  fruits;  and  there 
can  be  no  doubt  that  a  fuller  knowledge  of  the  subject  would  enable 
growers  and  shippers  to  avoid  much  of  the  loss.  The  present  bulletin 
is  prepared  in  response  to  requests  from  numerous  growers  for  informa- 
tion on  this  subject. 

The  Cause. — The  cause  of  the  rot  of  oranges  and  lemons  is  the  growth, 
through  their  substances,  of  a  mold  fungus  known  scientifically  under 
the  name  of  Penicillium  digitatum.  The  growth  of  this  plant  within 
the  fruit  causes  a  softening  and  breaking  down  of  the  tissue,  a  very 
characteristic  change  in  the  flavor  of  the  juice,  and  sooner  or  later  a 
very  pronounced  discoloration  of  the  affected  part.  The  fungus  belongs 
to  a  genus  consisting  of  a  number  of  well-known  species,  all  having 
much  the  same  manner  of  growth  and  producing  decays  on  various 
substances.  The  name  "blue  mold"  applies  to  the  whole  group.  The 
best  known  species  is  Penicillium  crustaceum,  or,  as  it  is  more  commonly 
called,  Penicillium  glaucum.  This  species  is  one  of  the  common  forms 
of  rot-producing  fungi  that  attack  deciduous  fruits,  but  it  is  probably 
even  better  known  from  its  attack  upon  all  manner  of  substances  in  the 
household,  such  as  cooked  foods,  clothing,  etc.  While  Penicillium  crus- 
taceum  is  thus  found  in  a  great  variety  of  situations,  it  appears  that 
Penicillium  digitatum  attacks  only  citrus  fruits,  confining  itself  wholly 
to  these. 

Nature  of  the  Fungus. — The  form  of  the  fungus  while  it  is  growing 
through  the  tissue  of  an  orange  is  that  of  innumerable  fine  white  threads, 
known  as  "vegetative  or  growing  mycelium,"  the  individual  threads 
being  called  "hyphae."  (Plate  1.)  These  hyphse  penetrate  the  fruit  in 
much  the  same  way  as  the  root-hairs  of  higher  plants  penetrate  the  soil. 
Indeed,  they  are  quite  similar,  except  that  the  hyphse  are  not  attached 
to  a  more  complicated  organ  like  the  rootlet  from  which  the  root-hair 


—  4  — 


Plate  1.    Vegetative  mycelium  from  a  culture  of  the 
fungus  in  water.    Very  much  magnified. 


^ 


v^KPr 


Plate  2.    Rotten  orange,  partly  unwrapped,  showing  mold  in  white  and 

blue  condition. 


—  5  — 


Plate  3.  Fruiting  hyphre  in  the  "  white  mold  "  con- 
dition. Surface  view  as  seen  under  the  microscope. 
The  same  fruit  shown  in  Plate  2. 


springs.  After  the  vegetative  mycelium  has  somewhat  exhausted  the 
substances  of  the  fruit,  or  if  the  latter  becomes  too  dry  for  rapid 
growth,  the  fungus  prepares  to  develop  a  form  of  fruit  of  its  own. 
Fruiting  hyphse  grow  outward 
to  the  surface  of  the  fruit,  or, 
as  is  sometimes  the  case  if 
there  is  a  cavity  within  the 
fruit,  they  grow  to  the  surface 
of  the  cavity  and  there  form 
the  fruiting  mycelium.  This 
is  a  dense  mass  of  threads, 
white  in  color  and  soft  and 
•downy  in  texture.  (Plate  3.) 
It  is  this  stage  of  the  growth 
that  the  growers  call  "  white 
tmold."  It  is  merely  a  stage 
in  the  development  of  the 
fungus  following  the  growth 
of  the  vegetative  mycelium 
within  the  fruit,  and  the  fruit- 
ing hyphse  are,  as  it  were, 
the  fruit  spurs  upon  which  the  crop  of  the  fruit  of  the  fungus  will  be 
borne.  The  fruit  of  the  fungus  consists  of  minute,  oval  bodies,  called 
.spores,  of  dull,  greenish-blue  color.     When  they  become  numerous  enough 

'J  *5  "*"*  ****?  #»~  ^°  ^ide  the  white   mycelium 

upon   which  they  are   borne, 

the  whole  surface  changes  to 

blue,   and   it   is    then   called 

"blue  mold."    (Plate  2.)    The 

V  ?Jm|l   fruiting  hyphse  producing  the 

I  spores  first  divide  into  a  num- 

|J§  ber   of    branches,    suggesting 

■ 

§f  the  name  of  the  species  ("  digi- 
gf  tatum,"  or  fingered),  and  each 
W    of  these  branches  as  they  in- 
crease in  length  become  con- 
stricted,   and    finally    divide 
into  a  large  number  of  oval 
fruits,  the  conidia-spores}which 
for  a  long  time  hang  together 
like  a  string  of  beads.     (Plate 
-4.)      They  are  easily  broken  apart,  however,  and  produce  then  a  fine 
powder  that  can  be  carried  by  the  wind,  and  so  are  distributed  far 
and  wide. 


fJW 


*;- 


4  •*■'* 


Plate  4.    Conidia-spores— still  more  enlarged. 


—  6  — 

There  is  another  form  of  fruit  produced  by  plants  of  this  genus 
Penicillium,  known  as  the  asco-spores,  being  formed  in  little  sacks  called 
asci;  but  they  occur  only  rarely,  and,  as  far  as  we  know,  have  not 
been  recognized  in  this  species.  They  doubtless  occur,  however,  and 
enable  the  fungus  to  pass  seasons  that  would  kill  most  of  the  conidia- 
spores.  The  conidia-spore  is  the  means  of  rapid  reproduction,  and  the- 
only  one  that  is  highly  significant  from  the  practical  standpoint, 
because  it  is  responsible  for  practically  all  of  the  infection  of  our  fruit 
with  the  rot  disease. 

When  and  Where  It  Enters  the  Fruit. — The  rot  of  citrus  fruit  is  not 


Plate  5.    Navel  orange,  showing  rotten  spot. 

usually  a  disease  of  the  orchard.  In  lemons  the  infection  occurs  almost 
entirely  in  the  curing-house;  and  in  oranges,  as  a  rule,  after  they  are 
packed  and  on  their  way  to  the  East.  Navel  oranges,  however,  very 
often  come  into  the  packing-house  badly  infected  by  the  disease.  The 
trouble  begins  at  the  navel  end,  and  may  be  scarcely  visible  from  without; 
though  commonly  a  slight  split,  or  perhaps  a  little  gum,  will  indicate 
the  point  of  entrance  of  the  fungus.  (See  Frontispiece  and  Plate  5.)  In 
this  case  the  trouble  clearly  arose  in  the  field,  and  even  began  before  the 
fruit  was  ripe.  It  is  usually  confined  to  a  limited  part  of  the  fruit, 
perhaps  the  upper  end  of  one  or  two  sections,  and  very  often  produces; 


—  7  — 

spores  within  the  cavity  caused  by  the  shrinkage  of  the  affected  tissue, 
so  that  the  affected  part  may  be  badly  discolored.  In  any  citrus  fruit  a 
bad  wound  of  the  surface  is  apt  to  be  followed  by  the  development  of 
the  disease  in  the  tissue  just  beneath,  with  the  general  characteristics 
specified  above  as  occurring  in  Navels. 

In  the  packing-house  or  in  transit  the  point  of  attack  may  be  the 
navel  end,  but  it  is  more  commonly  where  two  fruits  are  pressed 
together.  Usually  only  one  of  the  fruits  so  touching  is  affected  at  firsts 
though  after  it  becomes  thoroughly  rotted  the  disease  usually  communi- 
cates to  the  other.  If  the  conditions  are  favorable  to  the  growth  of  the 
fungus,  it  may  spread  from  a  single  affected  fruit  to  all  those  adjacent, 
and  in  time  to  the  whole  box. 

How  It  Enters  the  Fruit. — This  disease,  being  entirely  a  matter  of 
the  fruit  and  belonging  particularly  to  ripe  fruit,  evidently  always 
gains  its  entrance  to  the  fruit  from  the  outside  and  never  from  the  tree. 
The  conditions  necessary  to  accomplish  this  are: 

First — That  the  spore  of  the  fungus  should  rest  upon  or  near  the  sur- 
face of  the  fruit.  It  may  be  carried  there  by  the  wind,  or  by  touching 
decayed  fruit  upon  which  the  spores  are  being  produced. 

Second — Sufficient  water  upon  the  surface  of  the  fruit  to  cause  the 
germination  of  the  fungus. 

Third — The  right  condition  of  temperature.  The  fungus  will  grow  in 
such  a  range  of  temperatures,  however,  that  this  condition  may  be  con- 
sidered to  be  practically  always  present. 

The  germination  of  the  spores  of  the  fungus  is  thus  seen  to  be  much 
the  same  as  the  germination  of  the  seed  of  a  higher  plant. 

The  reason  that  the  navel  end  is  particularly  liable  to  the  attack  of 
the  rot  fungus  is  that  in  case  a  drop  of  moisture  finds  its  way  within 
this  structure,  it  is  less  liable  to  rapid  evaporation,  and  so  favors  the 
germination  of  any  spores  that  may  also  find  their  way  there.  The 
same  explanation  accounts  for  the  common  abundance  of  this  fungus  in 
fruit  with  broken  skin.'  The  point  at  which  moisture  will  accumulate 
and  remain  longest  when  fruit  is  sweating  after  packing,  or  while  it  is 
stored  in  the  packing-  or  curing-house,  is  the  point  where  the  fruit 
touches  an  adjacent  fruit;  and  at  this  point,  therefore,  the  germination 
of  the  fungus  most  commonly  occurs. 

PREVENTIVE    MEASURES. 

From  the  above  review  of  the  manner  of  growth  of  the  fungus  pro- 
ducing the  rot  of  these  fruits,  it  is  evident  that  our  preventive  measures 
must  lie  wholly  along  one  of  two  lines:  either  by  preventing  the  spores 
from  gaining  access  to  the  surface  of  the  fruit,  or  by  the  prevention  of 
the  germination  of  the  spores  after  they  are  there.     For  the  latter  pur- 


—  8  — 

pose  several  methods  have  been  employed,  usually  without  knowledge 
of  the  reason  of  their  efficiency,  and  therefore  often  in  a  manner  to 
defeat  the  very  object  sought.  Those  that  have  proven  valuable  are 
Refrigeration,  Ventilation,  and  Wrapping. 

Effects  of  Refrigeration. — One  of  the  most  available  means  for  abso- 
lutely preventing  the  growth  of  the  fungus,  even  though  abundant  upon 
the  surface  of  the  fruit,  is  to  so  lower  the  temperature  where  it  is  stored 
that  the  fungus  will  not  grow.  This  method  is  followed  very  largely  by 
shippers  of  green  deciduous  fruits,  who  have  to  contend  against  the 
closely  related  Penicillium  crustaceum.  If  sufficient  refrigeration  is 
maintained,  the  fruit  will  be  entirely  safe  from  the  attack  of  the  fungus. 
In  the  use  of  refrigeration  it  should  be  clearly  understood  that  the  cold 
temperature  is  likely  to  condense  a  large  amount  of  water  upon  the 
fruit,  and  as  soon  as  the  temperature  is  allowed  to  rise  to  the  point 
where  the  fungus  can  grow,  the  conditions  are  extremely  favorable  for 
its  rapid  germination.  This  has  given  rise  to  the  belief  of  many  that 
fruit  taken  out  of  refrigeration  is  much  more  subject  to  rot  than  it  was 
before.  The  skin  may  have  really  become  softened  by  the  water  during 
refrigeration,  so  that  this  may  in  some  measure  be  true.  The  common 
experience  that  washed  fruit  rots  worse  than  that  which  is  brushed  dry, 
may  be  true  for  a  similar  reason.  But  in  any  case,  the  presence  of 
water  upon  the  fruit  is  always  essential  for  the  entrance  of  the  fungus; 
and  if  fruit  taken  from  refrigeration  is  immediately  thoroughly  dried  by 
arranging  for  sufficient  ventilation,  there  would  be  no  greater  suscepti- 
bility on  account  of  the  cooling.  The  use  of  refrigeration  for  citrus 
fruits  will  probably  never  be  resorted  to  as  extensively  as  for  deciduous 
fruits,  for  the  reason  that  the  control  of  rot  is  not  so  difficult  a  matter. 

Effects  of  Ventilation. — The  use  of  ventilated  cars,  or  the  ventilation 
of  the  curing-house,  is  chiefly  calculated  to  prevent  the  rot  by  carrying 
off  the  moisture  that  may  accumulate  on  the  fruit  in  the  sweating 
process,  or  on  account  of  the  rapid  lowering  of  the  temperature.  The 
cooling  that  is  accomplished  by  the  evaporation  of  this  moisture  is 
sometimes  thought  to  act  like  refrigeration,  and  may,  it  is  true,  slightly 
decrease  the  rate  of  growth  of  the  fungus  after  it  germinates,  but  can 
not  produce  a  temperature  low  enough  to  prevent  its  germination  and 
growth.  Certainly,  the  important  matter  in  ventilation  is  the  rapid 
removal  of  any  condensed  moisture  that  may  gather  on  the  fruit.  If 
this  moisture  is  removed  promptly  enough,  so  as  not  to  give  time  for  the 
germination  of  this  mold  fungus,  the  fruit  will  not  decay,  but  will  stay 
sound  until  it  would  ultimately  dry  up  and  mummify. 

The  problem  in  ventilation,  then,  is  to  maintain  the  mean,  and  avoid 
on  the  one  hand  too  much  drying,  and  on  the  other  the  presence  of  water 


—  9  — 

for  any  considerable  period  upon  the  surface  of  the  fruit.  In  small  lots 
this  is  not  particularly  difficult,  but  in  larger  rooms  there  is  some  diffi- 
culty in  securing  a  uniform  ventilation;  and  therefore  it  is  desirable, 
especially  in  curing  lemons,  that  the  temperature  be  kept  as  uniform  as 
possible;  particularly  avoiding  rapid  lowering  of  temperature  that  might 
result  in  the  deposition  of  water  on  the  fruit. 

Effects  of  Wi^apping. — The  practice  which  is  almost  uniformly  adopted 
for  citrus  fruits,  and  which  is  rapidly  extending  also  to  deciduous  fruits, 
viz.,  wrapping  them  in  tissue  paper,  is  an  extremely  efficient  means 
of  decreasing  danger  from  rotting.  The  reason  for  this  is  that  the 
paper  absorbs  water  very  freely  and  will  take  up  a  very  considerable 
quantity.  The  paper  will  have  to  become  very  wet  before  it  will  give 
up  enough  to  the  spores  of  the  fungus  to  permit  them  to  germinate, 
and  so  it  regulates  the  matter  to  a  large  extent;  because  when  the  tem- 
perature falls  the  paper  merely  becomes  moist,  and  when  the  tempera- 
ture rises  this  moisture  is  evaporated,  and  if  there  is  fair  ventilation  it 
will  be  carried  off  and  the  fruit  never  become  really  wet.  If  the  fruit 
sweats  too  much,  however,  owing  to  poor  ventilation  or  rapid  lowering 
of  temperature,  the  paper  will  not  be  sufficient  to  prevent  the  accumu- 
lation of  the  water  on  the  fruit  and  the  germination  of  any  spores  that 
may  be  there.  Only  within  certain  limits,  therefore,  is  the  wrapping  of 
fruit  a  preventive  of  infection  by  the  fungus. 

DESTRUCTION    OF    THE    SPORES. 

Thus  far  we  have  considered  measures  that  have  been  employed  to 
prevent  the  germination  of  the  spores.  Quite  as  important  a  matter 
is  that  of  decreasing  their  abundance.  This  is  a  subject  that  has  not 
been  given  the  attention  that  it  should  have.  I  doubt  if  there  is  a 
packing-house  in  the  State  in  which,  in  the  midst  of  the  season,  the 
odor  which  is  so  characteristic  of  the  spores  of  this  fungus  is  not  at 
once  evident  to  every  visitor.  It  would  appear  almost  surprising  if  a 
single  fruit  could  escape  the  presence  of  the  spores  of  the  mold  upon  its 
surface  if  it  passes  through  some  of  the  packing-houses  in  which  the 
dust  is  so  filled  with  them.  The  means  that  may  be  employed  to 
diminish  the  number  of  spores  in  the  packing-  or  curing-house  are  of 
three  kinds:  disposal  of  infected  fruit,  disinfection  of  the  house  in 
summer,  and  the  use  of  sulfur. 

Disposition  of  Decayed  Fruit. — It  is  a  common  practice  to  throw 
decayed  fruit  in  a  pile  in  the  immediate  vicinity  of  the  packing-  or 
curing-house;  and  here  it  continues  to  decay  and  produce  countless 
millions  of  spores,  which  are  freely  carried  by  the  wind,  and  to  this  is 
due  the  thorough  infection  of  the  atmosphere,  referred  to  above.     There 


—  10  — 

is  no  means  better  calculated  to  disseminate  the  disease  than  this  prac- 
tice. Fruit  should  never  be  allowed  to  become  "  blue."  By  the  time 
it  reaches  the  white-mold  stage  it  should  either  be  destroyed  by  fire,  or, 
what  is  probably  more  feasible,  be  buried.  If  it  is  buried  deep  enough, 
go  that  it  will  not  be  turned  up  by  plowing,  or  in  any  other  manner? 
the  decay  of  the  fruit  will  be  completed,  and  in  time  the  spores  of  the 
fungus  will  disintegrate  and  the  disease  will  not  spread.  When  the 
fruit  is  stored  in  bins  for  some  days,  so  that  infected  fruit  will  have 
time  to  become  moldy,  these  moldy  fruits  should  be  removed  with  great 
care,  so  as  not  to  scatter  the  spores.  Attention  to  this  matter  can  but 
have  a  beneficial  effect  upon  the  prevalence  of  the  disease. 

Summer  Disinfection. — In  practically  all  parts  of  the  State  the  long, 
dry  summer  period  affords  a  very  available  time  for  the  thorough  disin- 
fection of  the  packing-house.  The  mold  spores  can  be  killed  by  pro- 
tracted drying,  and  it  should  be  the  practice  to  so  thoroughly  air  all 
packing-houses  during  the  hottest  and  driest  part  of  the  summer,  that 
they  will  be  entirely  free  from  the  fungus  for  the  beginning  of  the  next 
year's  campaign.  In  most  places  this  is  a  very  easy  operation,  and 
should  never  be  neglected  where  feasible. 

Sulfuring. — When  it  is  not  possible  to  disinfect  the  house  in  the 
summer  by  drying,  as  suggested  above,  or  by  whitewashing,  it  may  be 
possible  to  destroy  the  spores  by  the  free  use  of  sulfur.  This  is  also 
possible  during  the  actual  packing  season.  The  sulfur  should  be  burned 
so  that  the  fumes  will  come  in  contact  with  every  part  of  the  inside  of 
the  packing-  or  curing-house.  Usually  these  buildings  are  not  tight 
enough  to  permit  of  very  thorough  work,  so  that  no  prescription  of  the 
amount  to  use  can  be  safely  made.  The  material  is  not  expensive,  so 
that  the  best  policy  is  to  use  it  very  liberally  whenever  the  presence  of 
the  fungus  in  quantity  is  known  or  suspected  to  exist  in  the  house. 

ORCHARD    PRACTICE. 

A  great  deal  of  fruit  undoubtedly  goes  into  the  packing-house  already 
covered  with  the  spores  of  this  rot-fungus.  As  much  carelessness  in  the 
disposal  of  rotten  fruit  is  seen  in  the  orchard  as  has  been  pointed  out 
above  as  occurring  about  the  packing-house.  Rotten  fruit  is  very  com- 
monly allowed  to  fall  upon  the  ground,  and  is  turned  under  with  the 
plow,  to  be  turned  up  again  in  subsequent  cultivations.  In  almost  any 
orchard  in  which  the  disease  is  prevalent,  one  would  not  have  any  diffi- 
culty in  finding  oranges  or  lemons,  covered  with  quantities  of  mold- 
spores,  lying  upon  or  just  beneath  the  surface  of  the  ground,  from  which 
they  may  be  blown  over  the  fruit  with  the  dust. 

It  is  not  only  the  Navels  that  are  thus  endangered;  but  these  fruits 


—  11  — 

are  probably  the  only  ones  that  commonly  become  rotten  before  they 
are  picked.  All  the  fruit  in  the  orchard  is  liable  to  become  affected 
after  it  is  packed,  as  soon  as  the  spores  existing  on  its  surface  have  an 
opportunity  to  germinate.  It  is  particularly  desirable,  therefore,  that 
in  the  orchard  all  decayed  fruit  be  gathered  and  buried  so  deeply  that 
it  will  not  be  turned  up  by  the  plow;  or  that  it  should  be  otherwise 
disposed  of.  This  may  be  done  by  digging  a  deep  hole  every  little  dis- 
tance in  the  orchard,  and  piling  in  the  rotten  fruit  from  adjacent  trees. 
Another  method  would  be  to  gather  and  compost  decayed  fruit,  thus 
destroying  the  spores;  in  this  way  finally  using  the  fruit  for  fertiliza- 
tion, as  mentioned  by  Professor  Hilgard  in  the  paragraph  below. 
Either  method  provides  a  safe  and  rapid  means  of  disposing  of  the 
refuse  fruit,  which  will  certainly  very  materially  decrease  the  amount 
of  spores,  and  therefore  the  liability  to  rot. 


THE    FERTILIZING    VALUE    OF    CITRUS    CULLS. 

In  connection  with  the  foregoing  discussion  of  the  cause  and  preven- 
tion of  the  rot  of  citrus  fruits,  it  seems  desirable  to  discuss  a  point  very 
frequently  mooted,  viz.,  the  fertilizing  value  of  such  culls.  Since, 
from  Professor  Woodworth's  investigations,  it  is  clear  that  the  culls  are 
not  merely  useless,  but  a  positive  detriment  if  allowed  to  rot  under  the 
trees,  as  is  commonly  done,  the  question  of  their  disposal  raises  that  of 
their  value  in  restoring  the  plant-food  they  have  derived  from  the  soil. 
It  is  clear  that  each  fruit  represents  the  ingredients  which  will  be 
required  to  produce  another  in  the  future;  and  in  accordance  with  the 
golden  rule  of  returns  to  the  soil,  they  should  be  given  back.  The 
question  arises,  however,  as  to  the  exact  value  represented,  and  the 
expense  the  grower  can  afford  to  go  to  save  it,  as  against  purchasing 
fertilizers  in  the  market. 

The  ash-percentage  of  fresh  citrus  fruit  is  (in  California)  .43  per  cent 
on  the  average.  Analysis  shows  that  of  this  amount  about  one-half  is 
potash,  while  .053  per  cent  is  phosphoric  acid.  Or,  stated  for  1,000 
pounds  of  oranges,  we  have  2.11  pounds  of  potash,  1.25  pounds  of 
phosphoric  acid,  and,  besides,  1.83  pounds  of  nitrogen  in  the  fresh  fruit. 
Assigning  to  these  ingredients  their  accepted  commercial  values  for 
such  conditions,  we  find  the  manurial  value  of  the  1,000  pounds,  aside 
from  the  humus,  to  be-about  30  cents;  it  will  not  exceed  40  cents. 

As  an  alternative  of  the  deep  burying  recommended  by  Professor 
Woodworth  in  order  to  render  the  culls  innocuous  to  the  crop,  I  have 
heretofore  suggested  composting  with  lime  and  earth  on  special  piles* 
the  compost  to  be  hauled  out  to  the  orchard  after  the  complete  decom- 
position of  both  fruit  and  mold-spores.     Considering  that  the  culls  are 


—  12  — 

usually  gathered  into  piles  anyway,  this  would  involve  little  outlay 
beyond  that  for  lime;  and  for  this  purpose  the  spent  lime  from  the  beet- 
sugar  factories  would  be  available,  provided  it  were  sold  at  its  true 
manurial  value  only,  which  is  about  $2.30  per  ton  in  the  moist  condi- 
tion, or  $3  in  the  dry.  When  fresh  lime  is  used  it  will  be  best  to 
employ  it  in  the  unslaked  condition,  so  that  it  will  help  to  take  up  the 
moisture  from  the  fruit.  The  compost  thus  produced  would  be  a  sub- 
stantial addition  to  the  productiveness  of  the  grove.  But  each  one  must 
judge  according  to  his  location,  etc.,  whether  this  or  the  purchase  of 
fertilizers  would  pay  best.  The  tree  roots  would  eventually  find  the 
pits  in  which  the  culls  were  buried;  but  to  plow  them  in  deep  enough 
to  prevent  their  being  brought  up  by  the  plow  afterward,  would  need 
the  "master's  eye."     [E.  W.  H.] 


